The jury submitted multiple handwritten questions to Judge Sherry Stephens after the testimony of Detective Esteban Flores of the Mesa, Ariz., police department:

"When interviewing Mr. Alexander's roommates, did they ever show concern for his extended absence?"

"Did you ever check into their alibis?"

"Did Mr. Alexander have another boarder living in the house (and) were fingerprints of the boarder taken to see if they matched the scene?"

The questions suggested that the jury has not completely bought the prosecutions' argument that Arias, a jealous ex-girlfriend, drove to Alexander's house in 2008 and had sex with him before stabbing him 27 times and shooting him. His body was found five days later.

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Arias has admitted to killing Alexander, but told police it was in self defense. She initially lied to investigators about Alexander's death, saying at first that she was not in Arizona when Alexander was killed and, later, that she was there and witnessed intruders kill Alexander, according to interrogation tapes played in court this week.

But the jury remained doubtful, according to the questions they submitted after Detective Esteban Flores had finished his testimony today. Flores was the lead detective who spent hours interviewing Arias and encouraging her to confess to the murder.

The questions focused on whether police had investigated any other suspects before landing on Arias, asking about Alexander's two roommates and whether they noticed he hadn't been seen around the house for multiple days.

"They believed he was in Mexico already," Flores responded, referring to a trip to Cancun Alexander had planned to take shortly after the time of the killing.

The jury asked about the roommates' whereabouts during the attack.

"One was working, and the other was staying at his girlfriend's home, house sitting for her parents," Flores said.

He also said police analyzed the blood and handprints found at the scene of the crime, which matched Arias', and found that there were no matches to either of the roommates.

The questions came after eight days of evidence and testimony from the prosecution showing that Arias lied about her involvement with Alexander and his death. The defense has yet to call its own witnesses or lay out an alternate theory for Alexander's death.

Earlier in the day, they argued that Arias requested an inconspicuous rental car for her road trip to kill ex-boyfriend Travis Alexander, flipped the license plates upside down, and returned it with "Kool-Aid"-colored stains and missing floor mats, prosecutors said in court today.

In a police interview a month later, Arias repeatedly denied killing Alexander or being in his hometown, and asked cops if they could check the red light cameras near his home, noting that they could capture her license plate number. She also suggested that they search the rental car she had used for evidence.

Prosecutors presented the evidence about Arias' road trip today in the seventh day of her murder trial, interviewing the Budget rental car franchise owner who rented her the car and playing interrogation tapes from the Mesa, Ariz., police department.

Arias, now 32, is accused of murdering Alexander, 30, by stabbing him 27 times, slashing his throat, and shooting him in what prosecutors said was a jealousy-fueled road trip to his home. She could face the death-penalty if convicted.

Arias denied her involvement in the killing throughout months of police interviews, saying she had never held a gun or used a knife to stab someone and refusing to admit she was in Mesa at the time of Alexander's death.

She later altered her story to admit she had visited Alexander, but said he was killed by two masked intruders, a man and a woman.

Arias finally admitted to killing her ex-boyfriend and claimed it was self defense, saying that he was abusive and controlling. Her attorneys have called Alexander a "sexual deviant."

The owner of the Budget rental car agency where Arias rented the car testified today that she specifically requested a car that was not "loud in color." When he offered her a red car, she asked for a "lighter color car," Raphael Colombo, the Budget owner, said.

She rented a white Ford Focus from Colombo in Redding, Calif., and said she would only be driving locally with it, and then proceeded to drive to Arizona. There, she had sex with Alexander, took nude photos of him, and then killed him, before driving to Utah to visit a new love interest and then back to California, according to testimony made during the prosecution's arguments.

"When she returned it, the car had a little bit more miles on it for being local," Colombo said, noting that the car had driven nearly 3,000 miles.

The car also had two large, conspicuous red stains on the front and back seats. All four floor mats were also missing from the vehicle.

Colombo said he cleaned the stains, on the front passenger seat and the middle back seat, which had the largest stain.

"It appeared to be Kool-aid," he testified.

Prosecutor Juan Martinez also questioned Michael Galleti, a police officer who pulled Arias over when she was driving the rental car through Utah. He stopped her car after noticing the license plates were upside down.

"I saw that the rear license plate on the car was mounted upside down," Galleti testified."(Arias was) pleasant, and, I think, surprised to learn that the license plate was improperly displayed."

In interrogation tapes played in the courtroom a month after Alexander's death, Arias can be heard telling Detective Esteban Flores, the lead investigator, that she hadn't gone to Mesa and asked whether he had checked red light cameras for her license plate.

"No. Not unless you ran the red light," Flores said.

Prosecutors have also admitted receipts and cell phone records into evidence showing that Arias was in Mesa at the time of the murder and lied about her whereabouts.

In previous days' testimony, the prosecution has submitted nude photos that Arias and Alexander took of each other on the day he died as well as photos of Alexander in the shower just moments before he was killed.

After leaving Alexander's home in Arizona, she drove to Utah where she had a date with a new love interest, according to testimony.